fix: load .env via python-dotenv; SQLite default for local dev

backend/.env.example

@@ -0,0 +1,5 @@
+# Local dev — SQLite (no server required)
+DATABASE_URL=sqlite:///./innercontext.db
+
+# Production — PostgreSQL (set this in your deployment environment)
+# DATABASE_URL=postgresql+psycopg://user:password@host:5432/innercontext

backend/main.py

@@ -1,5 +1,9 @@
 from contextlib import asynccontextmanager
 
+from dotenv import load_dotenv
+
+load_dotenv()  # load .env before db.py reads DATABASE_URL
+
 from fastapi import FastAPI
 from fastapi.middleware.cors import CORSMiddleware
 

backend/pyproject.toml

@@ -7,6 +7,7 @@ requires-python = ">=3.12"
 dependencies = [
     "fastapi>=0.132.0",
     "psycopg>=3.3.3",
+    "python-dotenv>=1.2.1",
     "sqlmodel>=0.0.37",
     "uvicorn[standard]>=0.34.0",
 ]

backend/uv.lock

@@ -241,6 +241,7 @@ source = { virtual = "." }
 dependencies = [
     { name = "fastapi" },
     { name = "psycopg" },
+    { name = "python-dotenv" },
     { name = "sqlmodel" },
     { name = "uvicorn", extra = ["standard"] },
 ]
@@ -259,6 +260,7 @@ dev = [
 requires-dist = [
     { name = "fastapi", specifier = ">=0.132.0" },
     { name = "psycopg", specifier = ">=3.3.3" },
+    { name = "python-dotenv", specifier = ">=1.2.1" },
     { name = "sqlmodel", specifier = ">=0.0.37" },
     { name = "uvicorn", extras = ["standard"], specifier = ">=0.34.0" },
 ]